1. Field of the Invention
The present invention relates to a method of effectively recycling sludge discharged in a large volume and an apparatus therefor.
2. Description of the Related Art
Waste water is treated by biological waste water treatments such as an activated sludge method at a public sewage treatment plant, a night-soil treatment plant, a rural community wastewater treatment plant, or the like. However, a problem exists in that a treatment of sludge in a large volume produced from such treatment systems is difficult. Further, sludge has been conventionally treated follows. Settled sludge has been pulled out from a sedimentation tank or the like, dehydrated by a dehydrator, and incinerated or landfilled for disposal. Nevertheless, such disposal requires tremendous labor and time, and cost of transport, incineration, or the like is high. Moreover, from environmental concerns, dumpsites for the sludge discharged successively and growing enormous naturally become limited, and in the near future, respective local governments may not be able to assure dumpsites for the sludge.
Further, a sludge reduction method reported conventionally is not suited for mass disposal, and in practice, most of the sludge has been landfilled. Therefore, there still remains the need for dumpsites. Moreover, an investment for a large-scale treatment facility is necessary for the treatment, and a problem exists in that the cost of the treatment mounts. Further, a method of recycling residual sludge has been sought, but a particularly useful means has not been found.
Further, JP 2000-342670 A describes a method of degrading sludge or organic substances effectively, and a high reduction rate of sludge is indicated. However, a solution to the treatment of residual sludge has not yet been found.